Hull construction



Dec. 19 1922. 1,439,153

R. W. DAVIS HULL CONSTRUCTION FILED APR. 21 1921 tlllllllll 3 sHEE'Ts-sH ET 14 ef zid kzmnopq 11v V/g V TOR ESL BY PaefiMWaV/S A TTO AVEV Dec. 19 T922.

R. W. DAVIS. HULL CONSTRUCTION Fl LED APR. 21 I921 3 SHEETSSHEET 3 11v VENTOR Faber/- M 73510.? BY

A TTORNEY Patented lirl,

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thigh noennmw; DAVIS, or-NE /v YORK, N. Y. a

HULL .oonstrnrrorron.

Application filed April 21, 1921 Serial .No. 463,316.

To (ZZZ whom, it may concern Be it known that I, Ronnn'r W. DAvis,, a citizen of the United States; and a resident or the borough of Manhattan,-in the county. city, and State of. New York, have invented certain new and useful Improvements in Hull Constructions, '01 which the following is a specification. H

This invention relates in generalto mprovements in the. hull of a ship having means of propulsion applied endwise there. to,v and it appertains more especially to vessels driven by a propeller, positioned at one end thereof.

In screw propelled; ships as commonly built, the propeller is generally. mounted at the sternof the hull. and openates'to push it thru the water. -Vessels -are,,however, used wherein propellers are positioned both at the stern and the bow. l-i prevalent forinof vessel at the present time, asexempliiied by the boats ordinarily employed in. ferryservice, isequipped with a propeller at each end otthe hull. In boats of this character, it is thepractice eitherto. operate the propellers in unison. or thebow propeller is driven independently of the stern screw. lVhen the bow propeller is run by a. separate engine. it is toundthat the same revolves ,at a relativel slower speed thanthe one at the stern. This is due to .the I'Gtitl'Cllllg effect ot therushing volume of water back of the propeller being thrown against the bow of the hulh whichacts to impede the progress of the boat.

Tlheoroticallthe tractor. type otp'ropeh ler, i; e. a screwmounted at the bow of the boat. should give better results than a propeller oil the pusher species, e g! current or stream retardation could be ob viated.

pusher kind. and ifurthern ore fsquzittinf one lo-, rated at the stern, it, the consuleratmns oit' lesidesithe rudder ofthe boat will function more efliclently in relatively still water than in the washo'f a propeller ot the n: the stern ofv the boat. which occurs in.

J use.

ward end o f lthevessehthe latter is not only easier to maintain on the proper course in reaction of the socalled slip-stream upon the hull in order that, the coaction between the propeller and the hull,.may be eiiicient in pullingthe vessel at desired and requisite speeds. I I With the foregoing considerations in mind, ,tl1e= 11' a 1n;ob ect of the present invention is to provide a vessel ofuthetractor type wherein the retarding effect. of the wash from "the propeller on the hull willibe minimized. M 5

Anotherobject is to produce a hull. of the:

character described, in which the; drag of l the hull upon the water or the latter upon the former at the stern will-be reduced muclras possible, and the speed of thevessel maybe increased without augmenting this-action, p

A further objectis the.provisionwot a vessel of thenatnre. set forth whereby the stream from the propellerv is equally divided oujboth sides oi the hull and caused. to gather about the latter in a manner to buoy the bow; thereof and preventlit; from sinkingftoo deeply while. holding the b-oattoa straight course. i I

Still another object isthe production of a. vessel ofthe type specified so lformed at the bow that the heli *al oipswirling motion iniparted tothe water byjthe propellershall'be c i kept up as much as possible during itspassage along the hull; i

still tnrther object in producing a vesof thelolass mentioned is to furnish it withdeflectino; uritaces constructed and, arranged that part of the water looming from a propeller inounted atthebow of'the. hull shall beiguided1in.a longitudinal direction by; the sides oti the same without undue friction, orpretarding.action.

it generalyobject is to supply a. vessel of i the gen us. alluded; tonvhich. is thoroughly sea-worthy; capable L of being strongly built.

at reasonable cost. and whereinthe propelling power can be utilized with maximum advantage over the prevalent types now 111 vvention will become apparent the specification proceeds.

lVith the aforesaid objects in view, the

invention consists of the novel combinations and arrangements of parts hereinafter described in their preferred embodiments, pointed out in the'subjoined claims, and illustrated on the annexed drawings, wherein like parts are designated by the same reference characters throughout the several views' II In the saiddrawings I v Figure I- is a fragmentary side elevation of the bow of a'vessel showing the same constructed in accordance with the present invention, the "surfaces" thereof being shaded for the purpose of bringing out their configuration; I i

I I 's a view similar to the preceding,

the shading having been omitted, and spaced lines substituted to represent structural elements corresponding to similar parts in the other figures;

Fig. 111 is an end elevation looking from thelefthand side of Fig. L-s'urface shading being employed to bring out the contours of the parts; i

Fig. IV is a view to those shown inFig. II;

- Fig. Vis a plan viewlooking down upon the top side of Fig. I; and

Fig. V1 is also a plan, but viewed in an oblique direction according to an arrow A pertaining to Fig. IV. I f

Generally described, the inventionunder consideration includes in its organization a submerged prow extending forwardly of the bow of the hull from the bottom of the latter to about the light load water line thereof. This pro-w is given a twisted wedge shape. that 1s, the sides thereof have a heli-- cal formatiom and the propeller shaft bearing tube passes thru the middle of. the sharp end of thiswedge. The top and bot-.

tom faces of the prow which may be fiat for their ma or portions, are preferably tapered toward the same end and merge in offset relation one-to the other with the edge of the wedge. 'Thisedge which constitutes the stem of the prowis dividedsothat parts of thesame are tangenttofopposite sides of the propeller.shafttube. The helically formed portionsof'the prow which lie substantiallv withlnja p'roiectedtransverse plane bounded by the stems" extremities. guide the. water set in motion by the propeller along the hull, whlle those surfaces that are situated be yond the extremes of the divided stem, serve to deflect the water which is not directly acted upon by the propeller, out of thepath of the hull.

y The advantages of the invention as hereouthned are best realized when all of its like the last named,and I indicates structural elements corresponding featuresand instrumentalities are combined in the one and same structure, but, useful devices may bev produced embodying less than the whole. I I

It will be obvious to those skilled in, the art to which the invention appertains, upon becoming conversant with the details thereof, that thesaine maybe incorporated in several different constructions. The. accompanying drawings, therefore, are submitted merely as showing the preferred exemplification of the invention.

keel'of the vessel to substantially the light load water line thereof.

@Thesubmerged prow' 7 projects an ap preciable distance loeyond the remainder of the hull 6 and terminates at its forward end in a stem 8. The latter is obliquely disposed with relation to a central vertical plane passing longitudinally 'thru the hull, as shown to best advantage in Figs. III and IV, wherein the stem 8 is illustrated as being divided so that equal parts thereof are above and below a'propeller shaft hearing tube 9. The upper part of the said stem extends in diagonal tangential relation to the righthand side of the shaft tube in a general upward d irection','while the lower portion of. the stem runs diagonally tangent to the said tube in a like manner, hut downwardly from the left side thereof. The constructionshown in the drawings corresponds to an arrangement for associati on with a propeller turning in a clockwise direction, looking forward from the boa-t. I

It will be seen that a propeller shaft 11 extends thru the tube 9 beyond the forward end thereof, and has afiixed to it a propeller or screw of any appropriate type, such as shown at 12 in Fig. VI. The direction of rotationof; the propeller with reference to the hull constructiori'is indicated by an arrow B in this figure. Tt'will be' j nderstcod, moreover. thatany kind of engine or motor positioned within "the vessel may "be employed for driving the propeller, but in the layout shown, the parts as before thentinnedv are organized for co-o 'ieration with a screw (lfliell clockwise. However. it will be clear that if thepropeller is to be ro tated the opposite way and has a corresponding pitch, the shaping of the sub merged prow will be merely reversed, that is to say, the partswould be disposed so that the divided stem 8 would be inclined downwardly from the'left to the rightvon stead of from the righttothe'left as shown, In practice, the inclination of thesections of the stem may vary"from "3O degreesto (30 degrees. l levertheless, the angle of obliquity will depend to a large extent on the ward the right andt'lieother left, as viewed" in Figs. III and IV.

In the hull under considerationf as best seen in the shaded Figures I, III and V, it

will be noted that the portion of the sub- H merged prow which is situated to the left of the-sternS follows the curvature of a leftha'nd helix 14, whilethat on the right conforms to a siniil'arconvolution 15, but is oppositely disposed, the two'parts being arranged in the same manner as a twobladed auger. At a predetermined distance aft from the ste'ni these helices merge into the sides ofthe hull 6 which maybe straight or of any other configuration.

The surfaces lying'beyond the lines that follow the "adjacent differentially curved upper and lower edges of the helical portions 14 and 15 of the s'ubmergedprow and which constitute the top and bottom faces thereof, are denoted by the reference numerals l6 and 17 respectively. It will be observed from Fig. VI that a forward point 18 of the top surface 16 which coincides with the upper end of the stern 8 is bentor twisted so that a plane passingcentrally therethru comes at substantially right an gles to the working face of the propeller 12. a like condition prevailing with-reference to the surface 17 and its foremostpoint 19. The faces 1.6, l7,"ta-ken together with upper and lower parts 20, 21, which are bounded by acute curvededges as shown, and pertainingto the helices 1 1, 15 respectively, serve in conjunction with the there? to appertaining sections of the stem Spto (livide'the water into two separate currents of equal magnitude, that are deflected sidewise out of the way of the vessel, while the helical surfaces 1 15, tend to maintain the swirling motion imparted to the water by the propeller. thereby facilitating its ui'oveniei'it along the' hull. This arrangement not only obviates the retarding action of the water upon the'hull, but fur ther precludes the building up of back pressureimmediately in rear of the propeller.

In order that the shaping of the parts may be more clearly understood, when referring to the 's'eve'ral'figui'es of the drawln'gs, the structural elements constituting the helicalsur faces of the p'row,*-a're indicated iii sequence by the reference'letters n: to inclusive and they are represented in the same order in Figs. II, IV and VI, which exemplify similar positions'of the said elements! By comparingthese elementsin the several views, a comprehensive understanding of the configuration of the bow may be had.- The'cent-res from which the said ele ments radiate, are located about as far upward or downward, as they are offset outwardly from the axisof thepropeller 12.

arch of the helical surfaces 14,15 coinmences on'lines or planes constituting prolongations ofthe offset and divided stein portions 8. The'foremost parts of the prow includedbetween the said 'stem portions and theiroppositely disposed prolongations have been given the reference characters 22 and The latter "do not necessarily partake of the helical formation of the contiguous side faces 14 and 15 of which they consti-t tute acontinuatiom'but may be merely bent until thesaidparts 22' and 23 merge into their respective stem portions, the main purpose of the parts 22,- 28 being to separate the water coming fromthe propeller preparatorily to its reaching the said helical guiding surfaces. It is to benotedthat the places where thedeflection of the water occurs,'nan1ely, at or beyond the points 18,

19', that is, by the before named surfaces 20, 21, are so far offset froin the vertical centre of the vessel, that the outward movement of the water,the distance it has actually to be pushed to get out of the way of the hull, is

considerably less, iircomparison to what it would have to be moved ordinarily in a vessel having a perpendicular bow.

While the skin friction may be somewhat increased due to the higher speedot the watermoving past the helical surfaces 14, 15, this water is in longitudinal movement relatively to these'surfaces and is not thrown directly against diagonal sidesas heretofore. Ifthe vessel were-of old conventional form, the water from the propeller 'would be thrown "back against the'hull and thus be required to completely change its direction of flow upon eilcounte'ring the latter. Under suclrconditions the reaction on the hull would becons'idera-ble since the propeller actually operates; against itself, and in so doingimpedes the progress of l the ship to such an extent that an arrangement of this diameter is quite'impractical. Aside from the reaction, the building, up of back pres vertecl to,thru" a highly efiicient shaping of theprow of-the; hull, without complicating its constructions In practicethe present iii-- vention may be readily fabricated in hulls during the building thereof, or may be applied to vessels already constructed.

In the foregoing detailed description, the invention has been particularly described as associated with the forward portion of a ships hull of the tractor type. Nevertheless, the principles of the construction may be utilized to advantage in boats of thecombined tractor and pusher specie wherein propellers are positioned at both .ends ofthe hull, such for example, as in ferry boats. Invessels-of this character, the forward portion -or one end of the hull maybe formed in the manner specified, or both ends of the hull may be provided with the shaping herein exemplified. In practice it is deemed preferable that such a boat be furnished with a submerged prow at each end thereof,

so that it will operate with maximum efici ency in either direction.

Evenwith vessels of the pusher kind, improved results would be obtained with a stern formed according to the present invention, over one which is not provided with a twisted prow, or any of the prevailing types; Because, the water dragged away from contactwith surfaces that lead the same to the propeller'requires less work to beeXerted thereon than when it has, to leave diagonally disposed sides and then become deflected by the blades ofthe screw. The.

movement of the water from the longitudinal to the helical surfaces-isso gradual in a stern made accordingto this improved construction, that the water has timeto follow the contourof the hull and is accordingly fed with greater .efiiciency to the propeller, which is thus afforded a better grip and effects a maximum ofpushing power.

It will be understood, that when the present invention is employed in bow constructions for vessels of the-tractor type, the ater set in motion by'the propellers, and which does not pass the dividing edgeor stem 8, will move substantially parallel thereto. This isdue toa certain extentito the centrifugal force exerted by which. moves outwardly in both directions and is subsequently acted upon by the surfaces 20, 21 as hereinbefore explained.

In View of the fact that the water set in motion by the propeller is diverted in equal amounts to each side of .th'esutunerged.prow '7, it follows that a hullconstructed according to the principles described, can even under reduced speed be readily steered. Such a vessel will. be of especial value in canal navigation since there. will be nov tendency oflthe propelling means to draw the boat towards the nearest embankment of the canal,-because thewater is not sucked away from the hull, but is it. i For the same reason, a boat of this charin an outward direction the propeller .upon thev water,

rather gathered around acter will float lighter or have less submersion in shallow water than a stern propelled boa-t, WlllCll as well known always; sinks deeper in a canal or other shallow body of water.

While a certain preferred embodiment of' desire to secure by Letters Patent and claim,

L A hullLstruCture of the character described provided with diverging substantially helical surfaces, and means forpros pelling said hull located at the same end of the structure as said surfaces;

2. A hull structure of the character described having a portion shaped to resemble a twisted-wedge, and propelling means for saidstructure.disposed adjacent said portion.

3. A hull structure of the character described having one end thereof shaped to present spirally formed surfaces to the water, and a propeller coaxial with the axis of symmetry of said's'urfa'ces.

i. a hull structure of the character described having its bow provided exteriorly with. symmetrical substantially helical surfaces, and a screw propeller mounted adjacent 'aidsurfaces in coaxial relation therewith.

xi hull structure of the character de scribed provided at one end with substanti ally helical portions, and a propeller operativcly mountet adjacent said portions, the

latter diverging in a direction away from i said propeller. k

('3. A hull structure of the character described provided at one end on opposite sides thereof with substantially helical surfaces, and a propeller mounted for actuation adjacent the latter. I

7. A hull structure of the character described provided projecting portion of. substantially twisted wedge formation, and a propeller mounted for operation adjacent the outboard endof said portion.

S. A hull structure of the character dcscribed embodying a smiluerged tapered portion of substantiallyhelical exterior, and a propeller mounted for operation adjacent-- the outer end of said portion.

A bull structure of the character scribed embodying at one end a submerged twisted wedge portion, a shaftfextending longitudinally thru the latter, and a propeller mounted on said shaft adjacent the sharp] end of said Wedge portion.

10. Alhullstr ucture of the character de-' scribed provided at one end with a subat one extremity with a merged projecting portion resembling a twisted wedge a shaft extending thru the longitudinal centre of said portion, and a propeller operatively mounted on said shalt adjacent the outer sharp edge of said wedge, said edge of the latter being obliquely disposed relatively to a vertical plane passing axially of said propeller. I

11. A hull structure of the character described. einbodying a submerged prow of substantially twisted wedge formation, a shaft extending thru said prow, and a propeller mounted on said shaft adjacent the forward edge of the latter.

12. A hull structure of the character described having an obliquely disposed stein, a propeller located adjacent the latter, and water guiding surfaces leading in opposite directions from said stern in diverging relation to said propeller.

13. A hull structure of the character described provided with an obliquely arranged stem, a propeller disposed adjacent thereto,

and water guiding surfaces winding oppositely from said stem in diverging relation to said propeller.

14 A hull structure of the character described having at one end a divided obliquely disposed stern, a propeller operatively mounted in proximity to the sections thereof and helically winding surfaces diverging in opposite relation to said stern serving to guide the water to or away from said propeller.

15. A hull structure of the character described having at one end a divided obliquely arranged stem, a propeller shaft bearing tube interposed between the sections of said stem with opposite sides thereof in tangential relation to the same, waterguiding surfaces winding one right the other left hand above and below the stern, and a propeller cooperating with said surfaces mounted on the shaft journalled in said tube.

ROBERT W. DAVIS. 

